Dairy consumption in relation to psychological distress and sleep quality: findings from a large cross-sectional study in Turkish adults

Growing evidence suggests that dairy consumption may play a multifaceted role in human health; however, its simultaneous association with mental well-being and sleep quality remains poorly understood. This study investigated the associations between dairy product consumption and psychological status, and sleep quality in healthy Turkish adults. Data were collected from 4008 adults, including demographics, general health, and anthropometric measurements. Dairy consumption was determined using a semi-quantitative food frequency questionnaire, and daily intake was calculated. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI), and psychological status using the Depression, Anxiety, and Stress Scale-21 (DASS-21). Multinomial logistic regression models were used to examine the association between dairy consumption and psychological status, with adjustment for age, gender, and PSQI score. The mean age of participants was 37.9 ± 11.3 years (52%, female). In total, 2188 participants (54.6%) had poor sleep quality. Increasing stress, anxiety, and depression severity were associated with a lower likelihood of meeting the recommended dairy products intake. Specifically, moderate stress (OR = 0.61; 95%CI: 0.48–0.79; p < 0.001), extremely severe anxiety (OR = 0.51; 95%CI: 0.38–0.69; p < 0.001), and moderate depression (OR = 0.75; 95%CI: 0.60–0.95; p = 0.017) were associated with a lower probability of adequate dairy consumption. No significant differences were observed regarding sleep quality (p = 0.252). Higher levels of stress, anxiety, and depression were associated with a lower likelihood of meeting the recommended daily intake of dairy products, while no significant association was observed between dairy consumption and sleep quality. However, due to our cross-sectional design, these findings indicate associations rather than causal relationships. Therefore, both dairy consumption quantities and personal, psychological, and metabolic factors should be considered, and prospective studies are needed to clarify directionality.